Project Summary Chemosensory neuroscience has the ability to acquire relatively non-invasive recordings from all main stages of human olfactory processing but one, the olfactory bulb (OB). This lack of existing recording techniques poses a serious problem for the advancement of our understanding of how the human olfactory system works in health and disease. The General Aim of this application is to establish the first non-invasive method to acquire odorant responses from the human OB in a conscious human. Based on preliminary data, we hypothesize that signals obtained via recordings from electrodes at the nasal bridge represent responses from the olfactory bulb, so-called Electro-Bulbograms (EBG). In this project, we will conduct human subject research to determine if the recorded putative olfactory bulb signal originates from the olfactory receptors. We will utilize paradigms that have been shown in humans and other animals to clearly alter olfactory bulb responses, but not olfactory receptor responses. Moreover, we will determine whether the putative EBG signal originates from the olfactory bulb or from cortical structures by using paradigms demonstrated to alter signal in the cortex but not the olfactory bulb. The project will be performed by a team with a documented familiarity with all procedures, data analyses, and major technical aspects of the proposal. If successful, this innovation would not only enable explorations of the role fulfilled by the olfactory bulb in the human olfactory system but would also be easily implemented as an everyday clinical tool. For example, localizing disease-related changes in human central olfactory processing in neurodegenerative diseases (e.g., Parkinson?s disease) requires information about each stage of the olfactory pathway?information that is currently unobtainable. Thus, a technique allowing measures of human olfactory bulb signals will greatly aid future olfactory-related translational work.